As is generally well known in the prior art, diaphragms are an integral part of pumps. It is necessary in these applications for the diaphragms to be flexible in order for them to perform their intended function. However, the constant flexing of the diaphragm when the pump is in use creates stresses on the parts of the diaphragm that are attached to the non-flexing portions (i.e. outer piston, inner piston, pump housing) of the pump. Such outer and inner pistons are also referred to as follower and flange, respectively. Illustrated in FIG. 1 of the drawings is a typical example of a prior art arrangement of an outer piston and diaphragm used in many of these pump applications.
The inner and outer pistons contact preselected surfaces of the diaphragm and secure the diaphragm to the piston rod for reciprocal movement within the pump. These areas of the diaphragm normally exhibit rather severe wear and after extended use will eventually crack and/or have holes wear through the diaphragm. When this occurs the pump is out of commission until a new diaphragm can be installed to replace the worn out diaphragm.
In most cases the rest of the diaphragm is still in relatively good shape. Only at these wear points, under normal circumstances, does the diaphragm reveal excessive wear problems. The required replacement of the diaphragm is only one of the problems that maintenance personnel may encounter. The location of many pumps are such that they may be very difficult to get to and even after reaching the pump performing the work of replacing a diaphragm presents a challenge.
Thus, the longer a pump can be kept in operation without the need for servicing represents a considerable savings in not only the maintenance personnel's time but in the "up" time for whatever operation the pump is being used. Any improvement in either the formulation of the diaphragm or the configuration of the diaphragm and the inner and outer pistons that can increase its usable life expectancy is a welcome improvement.
The present invention is specifically related to improving the wear characteristics of a diaphragm at the aforementioned stress points related to abrasion by a outer piston.